I have prepared MATLAB code using ODE45 for calling function. Its giving error as "input argument 'z' is undefined. zp(1) = z(2); "

%apple solver code
x0=1e-6; %initial position
xp0=0;   %initial velocity
y0=1e-6; %initial position
yp0=0;   %initial velocity
tspan=[0 1e-4 0.296];
z0 = [1e-6; 0; 1e-6; 0];
[t,z] = ode45('apple',tspan,z0);
plot(t,z(:,1));
grid on

%%function for solver
function zp = apple(t,z)

m = 20;      %%mass of shaft in Newton
k = 170e6;   %%stiffness of bearing (k^inner = k^outer)
Pd = 20e-6;  %%diametral clearance of ball bearing
tp = 0.296;  %%time period
s=13;        %%Number of balls
wc = 21.26;  %%speed of bearing cage in rad/sec for 500rpm
si = 0;      %%angular location of defect on race of bearing
phi0 = 0;    %%initial position of ith ball

      for t =0 : 1e-2: tp %time increment
         for i = 1:1:s; %%ball increment
         phi(i) = 2*pi*i/s + wc * t + phi0; %%calculation of ith ball angle
         c = Pd/2 * (1 - cos(phi(i)));  %%calculation of radial clearance

              if phi(i) == si  %%condition for ball in region of defect
                  b = 1;
                  delta = 1.0586e-2; %%additional deflection of ball when it passes through defect
              else
                  b = 0; %%non-defective region
              end

              %solving Equation of motion for specified time period using
              %Runge Kutta method (ode45)
              %converting higher order equations into first order
          zp=zeros(4,1);
          zp(1)=z(2);
          zp(2)=(k*cos(phi(i))/m) * ((z(1)*cos(phi(i)) + z(3)*sin(phi(i)) - b*delta - c)^(3/2) - (z(1)*cos(phi(i)) + z(3)*sin(phi(i)) - b*delta)^(3/2));  %%((a - c)^(3/2) - (a)^(3/2)
          zp(3)=z(4);
          zp(4)=(k*sin(phi(i))/m) * ((z(1)*cos(phi(i)) + z(3)*sin(phi(i)) - b*delta - c)^(3/2) - (z(1)*cos(phi(i)) + z(3)*sin(phi(i)) - b*delta)^(3/2));
         end
      end
  end

[PRASHANT JAIN]

Hi, is above problem of code solved ?

Please send final code. Thanks.

Answer 1

[Walter Roberson]

Try changing to

[t,z] = ode45(@apple,tspan,z0);

and remember that you need to run apple_solver rather than apple

[ANIKET KADAM]

Thank you for your reply Sir. I ran apple_solver. and also '@apple' still same error

[Walter Roberson]

Your code only defines delta when phi(i) == si .

The filename you used when you attached was apple[1].m . The filename would have to be apple.m for MATLAB to be able to find the code. You might find you already have a different apple.m that is being invoked.